Radioreceiver



March 20, 1934. BRADLEY 1,951,542

RADIORECEIVER Filed April 14, 1933 2 Sheets-Sheet l W xix hig ATTORNEY.

March 20, 1934. F BRADLEY 1,951,542

RADIORECEIVER Filed April 14, 1933 2 Sheets-Sheet 2 Patented Mar. 20,1934 UNITED STATES PATENT OFFICE This invention relates to radioreceivers and the object of the invention is to provide a radio receiverarranged to receive all waves from the very short wave bands through thehigher broad cast wave bands.

One of the particular objects of the invention is to provide a series ofradio frequency coils arranged to cover the different wave bands andprovided with selector means for connecting the different coils into acircuit to receive the desired wave band.

A further object of the invention is to provide a standard on which thedifferent radio frequency coils are mounted and provided withtransversely aligned pin contacts for each coil and also provided with amovable bridge adapted to engage the pin contacts to connect therespective coil into the circuit, the bridge being movable by a rotatingshaft to engagement with the pin contacts of the different radiofrequency coils.

A-further object of the invention is to provide a device of thecharacter described in which the pin contacts are arranged in five rowsof four as transversely aligned pin contacts, each row providingcontacts for a single coil and the five rows providing contacts for thefive radio frequency coils.'

Another object of the invention is to provide a 30 bridge adapted to bemoved longitudinally of the standard and arranged to contact the contactpins for one coil at a time, the contacts to one coil being brokenbefore the next coil is brought into the circuit.

A further object of the invention is to elimihate the dead end lossesnormally occurring with a device of this character.

These objects and the several novel features of the invention arehereinafter more fully described and claimed and the preferred form ofconstruction by which these objects are attained is shown in theaccompanying drawings in which- Fig. 1 is a side elevation of a radioreceiver embodying my invention.

Fig. 2 is an enlarged section taken on line 2-2 of Fig. 1.

Fig. 3 is an enlarged section taken on line 3-3 of Fig. 1.

Fig. 4 is a diagrammatic circuit with which the device is used.

The device comprises an insulating standard 1 provided with end plates 2and 3. A shaft 4 is rotatably mounted in the end plates 2 and 3 as andis provided with a spiral groove 5 out therein. The end plates are alsoconnected by two guide rods 6 and 7, shown more particularly in Fig. 2,and a bridge 8 of insulating material is provided having guide brackets9 secured thereto and movable longitudinally of the guide rods 6 and 7.A bracket 10 is also secured to the center of the bridge and is providedwith a nut portion 11 carrying two pins 12 and 13 riding in the spiralgroove 5 and engaging in said groove on opposite sides of the shaft 4.By this arrange 66 ment, the shaft 4 may be rotated to move the nutmember 11 and bridge longitudinally of the shaft in either direction. Aselector plate 14 is stationarily mounted on the panel 15 so that theshaft 4 is rotatable therein and this plate is provided with a series offive recesses 16 into which the spring arm 17 may engage by turning theknob 18. At each end of the standard 1, a pair of brackets 19 areprovided and a pair of longitudinal insulating strips 20 are mounted onthese brackets.

For use with this device a series of five radio frequency coils areprovided in which one coil covers a range from sixteen to thirty meters,another coil covers a range from twenty-nine to fifty-eight meters,another coil covers a range from fifty-four to one hundred and fivemeters, another coil covers a. range from one hundred to two hundredmeters and the remaining coil covers a range from two hundred to fivehundred and ten meters. Two of these coils 21 and 22 are provided on onestrip 20 on one side of the device, as shown in Fig. 1, and two coilsare provided on the other strip 20 on the right side of the device ofwhich only the coil 23 is shown in Fig. 2. The fifth coil 24 is mountedbetween the two insulating strips 20.

Each coil is provided with a primary and secondary winding and on thecoil 23, the primary winding bears the number 25 while the secondarywinding carries the number 26. At the bottom, each coil is provided withfour pins 27 which extend through the insulating strips 20. The fourpins are arranged to provide two terminal contacts for the primary andtwo terminal contacts for the secondary winding. The primary leads 28and 29 are connected to the contact pins 30 and 31 and the secondaryleads 32 and 33 are connected to the contact pins 34 and 35. Thesecontact pins are mounted in the insulating standard 1 and extenddownwardly therefrom and are arranged so that the four pins are inalignment transversely of the standard.

The bridge 8 carries a set of four contact brackets 36 adapted to bemoved into contact with the standard 1.

four contact pins, the four contact brackets 36 being aligned on thebridge 8 so as to contact the four contact pins simultaneously.

As will be understood from Fig. 1,- each coil is connected to a seriesof four contact pins similar to those shown in Fig. 2 and the five rows,as shown in Fig. 1, are aligned transversely of the As shown in Fig. 2,the contact pins are also aligned in four rows longitudinally of thestandard 1. A longitudinal contact strip 37 is supported beneath thestandard 1 adjacent to and parallel with each longitudinal row ofcontact pins and each contact bracket 36 is provided with a springcontact arm 38 riding in contact with the respective contact strip 37.Each contact strip 37 is provided with a lead 39 which is carried out tothe end plate 2 and connected to a terminal 40, as shown at the left ofFig. 1. By this arrangement, four contacts 40 are provided in the endplate 2 for the four contact strips 37.

In operation, by turning the shaft 4, the bridge 8 is moved to bring thecontact brackets 36 into engagement with the four contact pins 30, 31,

34 and 35. When this is done, the secondary.

contact pins 34 and 35 are electrically connected through the brackets36 and spring arms 38 to the respective contact strips 37 and thesecontact strips arearranged to be connectedinto a radio receiving circuitby means of the terminals 40 to which the circuit leads may beelectrically connected. At the same time, the primary contact pins 30and 31 are also electrically connected by means of the contacts 36 and38 to the respective contact strips v37 which are also connected bymeans of the terminals 40'into a receiving circuit.

Should the operator desire to receive another wave band, he continuesrotating the shaft 4 to move the bridge 8 to contact the contact pinsfor the succeeding coils until the desired coil is properly connectedinto the circuit. i 1 By means of the spring arm 17 and the recesses 16in the selector plate 14, the different tuning coils may be readilyselected as the spring arm 17 drops into the respective recess as thecontact brackets 36 contact the contact pins for the respective coils.By this arrangement, the operator may feel and see when the desiredtuning coil is connected into the circuit.

A circuit for use in connection with this device is showndiagrammatically in Fig. 4. in which 25a, b, c, d and e represent theprimary windings of the five radio frequency coils, while 261:, b, c, dand 4 represent the five secondary windings. The tuning condensers 41,42 and 43 may be arrangedon separate shafts and a detector tube 44 isprovided as well as an amplifier tube 45 and a rectifier tube 46 whichis used in conjunction with the usual 110 volt alternating currentsupply. The out-put contacts 4'7 may be connected to a speaker or headphones as desired.

It will be noted in moving the bridge that the bridge may be moved inone direction by turning the shaft 4 in a clockwise direction and may bemoved in the opposite direction by turning the shaft 4 in acounter-clockwise direction and the guide rods 6 and 7 act as guides toprevent twisting action of the bridge and hold the contact brackets onthe bridge in position to contact the four respective contact pins ofeach coil simultaneously.

As will be noted from Figs. 1 and 2, the coils 'are arranged indifferent angular positions in in Figs. 1 and 3 may, if desired, beprovided with indications on the face thereof to indicate the wavelengths or kilocycles of the different coils so that in turning the knob18 and arm 17 the operator may readily see which coil is connected intothe circuit.

From the foregoing description it becomes evi dent that the device isvery simple and efficient in operation, will not easily get out oforder, provides a positive means for connecting different radiofrequency tuning coils into a circuit by rotationof a knob and providesa device which accomplishes the objects described.

Having thus fully described my invention, its utility and mode ofoperation, what I claim and desire to secure by Letters Patent of theUnited States is-- 1. In a radio receiver, a standard, a series of radiofrequency coils mounted on the standard, a row of contact pins for eachcoil mounted in alignment transversely of the standard and electricallyconnected to the respective coil, the contact pins of the differentcoils being also mounted in alignment longitudinally of the standard, acontact strip mounted parallel with and in spaced relation with each rowof longitudinally aligned contact pins, a bridge extending transverselyof the standard and provided with aligned contact brackets arranged toengage each row of transversely aligned contact pins simultaneously,each contactbracket being provided with a spring arm electricallyconnected thereto and riding in engagement with the adjacent contactstrip, the electrical connections for the contact strips being mountedat one end of the standard and means for moving the bridgelongitudinally of the standard to bring the contact brackets intoengagement with the successive transverse rows of contact pins.

2.'In a radio receiver, a standard, a series of radio frequency coilsmounted on the standard, a row of contact pins for each coil mounted inalignment transversely of the standard and electrically connected to therespective coil, a bridge extending transversely of the standard andprovided with aligned contact brackets arranged to engage each row oftransversely aligned contact of the series may be placed in circuitthrough the positioning of the spring arm with the corresponding recessof the selector plate.

3. In a radio receiver, a standard, a series of radio frequency coilsmounted on the standard, a series of contact pins for each coil andextending to the under side of the standard and arranged in rows bothlongitudinally and transversely of the standard and electricallyconnected to the respective coil, a contact strip for each longitudinalrow of pins, a bridge extending transversely of the standard andprovided with aligned contact brackets arranged to engage each row oftransversely aligned contact pins and each contact strip simultaneously,a rotatable shaft, means for moving the bridge longitudinally of thestandard by rotation of the shaft, a stationary selector plate, a knobfor rotating the shaft and a pointer carried by the knob and movableover the face of the selector plate.

4. In a radio receiving set, a standard, a series of radio frequencycoils differing one from another as to frequency and each having aprimary and a secondary winding, a series oi-pins for each coil, twoproviding terminal contacts for the primary winding and two providingterminal contacts for the secondary winding, the said pins of each coilbeing mounted in the standard in a row transversely thereof, similarcontact pins for each coil lying in longitudinal rows, a contact stripfor each longitudinal row of pins connected with the receiving circuitof the set, a bridge moveable longitudinally of the standard having aseries of contacts equal in number to the number of pins 01' a coil andpositioned in a row transversely oi the standard, said standard alsohaving a contact adjacent each of the last named contacts for thecontact strips companion to each longitudinal row 01' pins, means forcausing movement of the bridge longitudinally of the standard to placethe successive coils in the receiver circuit, and an indicator inconnection with said operating means enabling the operator to determinethe coil in circuit with the set.

FREDERICK H. BRADLEY.

